Electric safety-lantern.



T. A. EDISON. ELECTRIC SAFETY LANTERN. APPLICATION HLED ocT. 16. 1914.

1,366.1??9. Patend May 21,1918.

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TJEIEIS A. EJDISON, 01E' LJLEWELIFYN PARK, WEST ORANGE, NEW JERSEY, ESSIGNOE, T0

EEKSOEI' STOEAWE BATTERY COMPANY, 0F WEST OEENGE, NEW JERSEY, A CURP@- Eidlllitlltl' @E NEW JEESEY.

ELECTEJIG SAFETY-LENTEEN,

Speeiucation of Letters Patent.

Patented lllay 21, 1216-.,

application died Uctober 16, 19M. Serial 16o. 666,913.

have invented certain new and useful 1m-' provements in Electric Safety-Lanterns, of which the following is a description.

My invention relates to electric 'safety lanterns which, while adapted for general use, are especially designed for use in mines, tunnels", powder magazines and other places where readily combustiblev gases or other materials of a highly combustible or explosive nature are liable to be present.

rllhe principal object of my invention is to provlde a simple and an improved lantern of this character and one of such condll struction asto insure a ainst the ignition of gases or other combustible materials thereby, especially in case of damage to the lantern. A

@ther features of my invention reside in the details ofconstruction and combinations of elements hereinafter more fully described and claimed.

ln order that my invention may be more `clearly understood, attention is directed-tov the accompanying drawing forming a part of this specihcation and in which- Ei re 1 represents a central cross sectiona view, ypartly in elevation, of a prefer-red form of my improved lantern showthe lamp circuit open; and ig.. 2 is a similar circuit closed..

y1`lie same reference characters are used throughout the drawing to designate corresponding parte. s

Referring to the drawing, reference character 1 represents the lamp casing which preferably comprises a parabolic redector 2, |preferablyl formed of metal, and a cylindrical hollow chamber 3 suitably secured to the rear end of the redector, preferably by being brazed thereto. Suitably secured to lill the rear end of the chamber 3,as by being lthreaded thereto at 4L, is a hollow cap or cup-shaped member 5,."this member serving to fasten a dexible diaphragm 6, preferably formed of metal, against the open rear end ofthe chamber 3 in duid tight e w1: uw

' therewith. The front end 'of the rcdector is provided with an annular seat l and ia view showing the lampv Huid tight. The rear e'nd of the re ector is provided with an opening 11 communicating with the chamber 3, in which opening isdisposed a lamp socket 12. 'lhe forward end of the lamp socket is provided with a flange 13 which is suitably secured, as by brazing, to the redector about the opening 11 therein. The Hange 13 is provided with one or more apertures lll whereby communication is established between the interior of the rehector 2 and the chamber 3. Secured to tlie cup-shaped member is a tubular member preferably formed of thin sheet metal and comprising a vertical portion 15 and a rearwardly extending portion 16. Flexible conductors 17 and 18 are ldisposed within the tubular member and extend from the vertical portion 15 thereof into the cupshaped member 5 and from the end of the rearwardly extending portion 16 for connection with a suitable source of current, such as a storage battery (not shown). The end of conductor 17 within member 5 is grounded to the latter as by means of a bindin screw 19 and the corresponding end of con uctor 18 is connected to a stationary contact 20. Contact 20 is preferably in the form'of a screw and is threaded into an insulating block 21 which is secured to the end wall of the cup-shaped member 5 as by means of a screw 22. An insulating strip 23 is disposed between the block 21 and the end wall of member 5 to insulate the end of screw 20 from said wall.

An incandescent lamp 2d is dis osed within the redector 2, the plu thereof eing threaded into the socket 12. v he lamp plug is provided with a button 25 which constitutes one terminal of the lamp. 'lhe exible diaphragm 6has secured to one side thereofl a light metallic spiral-spring 26 adaptedto forced or pumped into the chamber but which eectivel'y prevents the escape of fluid therefrom. This valve comprises a tubular valve casing or sleeve 29 threaded into an opening provided in the wall of chamber 3, the outer end portion of the valve casing being internally screw threaded and the inner end portion thereof being provided with an internal annular flange 30. Reference character 31 represents a check valve which is provided with a stem 32 passing loosely through the flange 30 andhaving at its inner end a shoulder 33. A. compressed coiled spring 34 surrounds the valve stem 32 between its shoulder 33 and the annular flange 30 of the valve casing and constantly tends to hold the valve 31 against the seat therefor [rovided by the inner end of the casing 29.

eference4 character 35 represents a capwhich is threaded into the internally screw threaded end portion of the valve casing and prevents dirt from entering the latter and also serves as additional means for preventing the escape of fluid from the lamp.

casing.

In order that the lantern' may be readily and securely attached to an object such as the ordinary miners cap, I provide the samev with af substantially U-shaped bracket 40. One leg 41 of this bracket is suitably secured lat its end,as by means of screw 22, to the end wall of the cup-shaped member 3, while the other leg 42 thereof is in the form of a spring finger or hook and is adapted to extend through the usual aperture in the top of the lantern supporting bracket of a miners the terminal 25 of the lam `under such a compression t at, when the cap and to press against the rear of this bracket. The bracket 40 is provided at its base with a stirrup 43 through which the rearwardly extendingportion 16 of the tubular member containing the conductors 17 and 18 extends. A screw 44 is threaded through the stirrup 43 and acts to fasten the bracket 40 more securely to the lantern. The tubular portion 16 is preferably slitted to provide the same with a resilient strip 45 in the up er portion thereof and the screw 44, in addltion to the functionq'ust described, also acts to prevent the breaking of the connections between the conductors 17 and 18 and screws 19 and 20 by forces applied to the conductors beyond the lantern, by depressing the strip 45 to thereby firmly clamp the conductors 17 and 18 between the latter and the lower portion .of the tubular member, as clearly shown in Fig. 1.

The flexible diaphragm 6 normally tends to assume the position shown in Fig. 1- and when in this position the stiffI spring 27 will be disengaged from contact 20. The li ht spring 26 will then be in engagement with and will be diaphragm is flexed to its operative position in which spring 27 engages contact 20 to close the lamp circuit, it will merely expand without disengaging the terminal 25, as shown in Fig. 2.

When the lantern is operative the path of the current therethrou h is as follows: through one conductor 1 to binding screw 19, then through the walls of cup-shaped member 5, chamber 4 and reflector 2 to the lamp socket 12, then through the lamp 24 and terminal 25 thereof, spring 26, diaphragm 6, spring 27 and contact screw 20 to the other conductor 18.

To render the lantern operative, the fluid tight casing 1 is supplied with sufiicient fluid pressure, by forcing fluid thereinto past the check valve 31, to flex the diaphragm to the position shown in Fig. 2 and thereby close the lamp circuit. In ease of such damage to engagement with the contact 20 and thereby breaking the lamp circuit.

The use of the spring 26, which is not attached to the lamp, but merely loosely enages one terminal thereof, and the manner 1n which the lamp is mounted enables the lamp, when broken or burned out, to be very readily replaced.

The form of springs 26 and 27 and the manner in which they are mounted and coact with the lamp terminal 25 and the screw 20 are such as to insure a very effective contact between the said springs, terminal, and screw, somewhat in the nature of a sliding contact.

While I have specifically described the preferred embodiment of my invention, it is to be understood that many changes may be made in the size, form and arrangement of the parts thereof without any departure I from the spirit of the invention and the scope of the appended claims.

Having now described my invention what I claim as new and desire to protect by Letters Patent is as follows:

1. In an electric safety lantern, an incandescent lamp and an electric circuit including said lamp, a contact, and a device comprlsing flexible means disposed between said contact and one terminal of the lamp and movable with respect to said contact to effect the making and breaking of the circuit, said flexible means normally tending to assume circuit breaking position and being provided with resilient conducting means unattached to the lamp but engaging one terminal thereof in all positions of the flexible means, substantially as described.

2. In an electric safety lantern, an incandescent lamp, and an electric circuit including said lamp, a contact, and means comprlsing a flexible diaphragm movable With respect to said contact to elfect the making and breaking of the circuit, said Hexible diaphragm normally tending to assume circuit breaking position and being provided on one side thereof with a coiled spring unattached to the lamp but engaging one terminal' thereof in all positions of the {ilexible diaphragm, substantially as described.

3. In an electric safety lantern, an incandescent lamp, and an electric circuit including said lamp a contact and a flexible dia phragm movable with respect to said contact to eHect the making and breaking of the circuit, said diaphragm normally tending to assume circuit breaking position, being provided on one side thereof with resilient means unattached to the lamp but engaging one terminal thereof in all positions of the diaphragm, and being provided on its other side with resilient means adapted to engage and disengage said contact, substantially as described.

4. In an electric safety lantern, a fluid tight casing comprising a reflector and a hollow7 chamber communicating therewith, one wall of said chamber comprising a flexible member, an incandescent lamp disposed within said reflector, and an electric circuit including said lamp, said flexible member being movable under variations in Huid pressure in said casing: to effect the making and breaking of said circuit, substantially as described.

mounted in said casing 5. In an electric safety lantern, a uid tight casing comprising a reflector anda hollow chamber, one Wall of the chamber comprising a flexible member, said reflector being provided with an opening communieating with said chamber, a lamp socket secured to said reflector about said opening and being provided with means establishin communication between said chamber an reflector, an incandescent lamp mounted in said socket, and an electric circuit includin said lamp and said flexible member, said flexible member being movable under variations in fluid pressure in said casing to effect the making and breaking of said circuit, substantially as described.

6. In an electric safety lantern, a fluid tight casing one wall of which comprises a flexible diaphragm, an incandescent lamp an electric circuit including said lamp and controlled by said diaphragm, said diaphragm normally tending to assume circuit breaking position but being movable by Huid ing to circuit closing position, and a resilient member secured to said diaphragm and unattached to but engaging one terminal ofi said lamp when the diaphragm is in either of said positions, substantially as described. rlihis specification signed and witnessed this 13th day of October 1914.

THUS. A. EDISON. Witnesses:

WIILIAM A. HARDY, MARY J. LAmLAw.

pressure 1n said cas- 

